Faulty fuel level sender (second unit) inside the tank, such as a worn resistive track or wiper; Wiring or connector fault on the sender signal or ground circuit, including corrosion or chafing; Fuel pump module or sender connector at the tank damaged or corroded; Sender float stuck, damaged or fouled, or tank fitted with a deformed internal component; Fuel transfer problem between the two tank sides, so one side does not empty or fill as expected; Control module fault or outdated software, where a known fault is documented for the model.

P1431

Fuel Level Sensor 2 Performance.

Cadillac
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
4: AreaAuxiliary emission controls
31: FaultThe specific fault in that area

What it means

P1431 on a Cadillac means the control module has judged the performance of the second fuel level sensor to be implausible. This is typically on vehicles with a saddle-type fuel tank that has two sender units. The module saw the signal stuck, erratic, out of range or not changing as expected against fuel use, or disagreeing with the other sender.

Symptoms

Fuel gauge reads wrongly, sticks or jumps about
Fuel gauge does not reach full after filling, or drops suddenly
Low fuel warning light on at odd times
Malfunction indicator lamp on
Inaccurate range or fuel economy readout

Possible causes

Faulty fuel level sender (second unit) inside the tank, such as a worn resistive track or wiperlikely
Wiring or connector fault on the sender signal or ground circuit, including corrosion or chafinglikely
Fuel pump module or sender connector at the tank damaged or corrodedpossible
Sender float stuck, damaged or fouled, or tank fitted with a deformed internal componentpossible
Fuel transfer problem between the two tank sides, so one side does not empty or fill as expectedpossible
Control module fault or outdated software, where a known fault is documented for the modelrare

How to diagnose

Read all stored codes and freeze frame data, noting fuel level and any other fuel level or fuel system codes
Compare the fuel gauge reading with the real fuel level and note how the reading changes when the tank is filled
Watch live data for both fuel level sensors and see whether the second one is stuck, noisy or out of range
Inspect the wiring and connectors from the tank to the module for damage, water ingress and corrosion
Check the sender signal, reference and ground circuits for continuity, short circuits and voltage drop, following the model's wiring diagram
Measure the sender resistance across its travel against the manufacturer's specification for the model
Inspect the sender and float for damage or sticking once the tank is safely accessed, and check the fuel transfer arrangement
Check for relevant software updates or service bulletins for the model and engine

How to fix

Replace the faulty second fuel level sender or the module that contains it
Repair or replace damaged wiring and clean or renew corroded connectors
Renew the tank connector or pigtail if the terminals are damaged
Correct any fuel transfer fault between the tank sides
Update the control module software only where a known fault is documented, and replace the module if it is proven faulty

Can I keep driving?

Low severity

The car can normally be driven, but the fuel gauge may be unreliable, so track mileage and refuel early to avoid running out. Book it in for repair soon.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.